Along an assembly line, diapers and various types of other absorbent articles may be assembled by adding components to and otherwise modifying an advancing, continuous web of material. For example, in some processes, advancing webs of material are combined with other advancing webs of material. In other examples, individual components created from advancing webs of material are combined with advancing webs of material, which in turn, are then combined with other advancing webs of material. Webs of material and component parts used to manufacture diapers may include: backsheets, topsheets, absorbent cores, front and/or back ears, fastener components, and various types of elastic webs and components such as leg elastics, barrier leg cuff elastics, and waist elastics. Once the desired component parts are assembled, the advancing web(s) and component parts are subjected to a final knife cut to separate the web(s) into discrete diapers or other absorbent articles. The discrete diapers or absorbent articles may also then be folded and packaged.
For quality control purposes, absorbent article converting lines may utilize various types of sensors to detect defects in the webs and discrete components added to the webs along the converting line as absorbent articles are constructed. Example sensor technology may include vision systems, photoelectric sensors, proximity sensors, laser or sonic distance detectors, and the like. Sensor data may be communicated to a controller. In turn, the controller may be programmed to receive sensor data and reject or cull defective diapers after the final knife cut at the end of the converting line.
Various systems are used for rejecting defective diapers, such as by diverting the defective diapers from the stream of diapers that are of satisfactory condition or good quality. For example, one system that has been used to reject cut web products includes forcing the defective diapers out of the stream of satisfactory products by using pneumatic air blasts, which divert the defective diapers to a path that differs from that for the stream of satisfactory diapers. In such a method, the defective diapers are detected, and a pneumatic air blast from one or more nozzles forces the defective diapers out of the stream of quality products and into a reject bin provided in proximity of the conveyor system or production line. Such existing systems of rejecting cut web products using pneumatic air blasts may have some disadvantages. For example, a separate system having pneumatic nozzles and associated hoses and/or piping require space, such as for example, extra space along the conveyor system. In addition, such systems may not be entirely accurate and can divert more than solely the defective diapers from the stream of satisfactory products.
Other methods of rejecting defective diapers may include mechanically activated switches, or flippers, that divert the defective cut web products to an alternative pathway, similar to the manner railway switches can divert trains to a different track. The mechanical switches are may be activated via a pneumatic or hydraulic cylinder or via an electric motor. Some configuration may include mechanical switches that pop up from the conveyor system and divert the defective diapers below the switch and toward an alternate pathway. With such mechanically operated systems, more space may be required to accommodate the mechanically activated switches. Thus, space consumption is a disadvantage to the mechanical switch method. Furthermore, the additional mechanical switch equipment may result in added complexity and cost.
Consequently, it would be beneficial to provide a relatively less complex and less spacious system for high speed selective redirecting and/or rejecting of absorbent articles. In addition, a method and apparatus that is relatively more accurate in removing only the defective absorbent articles from the stream of quality products may also be desirable. Further, a system that utilizes some existing converting equipment and control mechanisms to reject products rather than a completely separate system to perform redirecting and/or rejecting operations may be desirable.